The Unmatched SP Bets window is only displayed when there are unmatched SP bets that have been placed with the Set SP Odds Limit turned on. It allows you to lower the minimum odds for unmatched Back SP bets and raise the maximum odds for unmatched Lay SP bets. Once submitted an SP bet cannot be cancelled in addition the minimum odds cannot be raised on unmatched Back bets and the maximum odds cannot be lowered on unmatched Lay bets.